Flashcards in Unit 8: Biodiversity, Viruses (8.2) Deck (24):
First person to isolate a virus
The virus Wendell Stanley isolated
The virus was Tobacco Mosaic Virus - TMV
Viruses possess either a ______ or_________ strand of DNA or RNA. (This is how viruses are classified.)
Viruses contain very small amounts of _____ or ______– most are 4 to 500 genes total.
The 2 purposes of the Capsid (Viral Protein Coat)
1. Protection of the DNA or RNA strands inside.
2. Attachment of the virus to a host cell.
The capsid is built from protein units called ___________. (means “capsid unit”)
Some viruses can also have a ______ _________.
This is a cloak derived from the previous host cell plasma membrane. (It is an example of mimicry. It looks like a normal cell, but it is actually like a Trojan horse. The danger is inside.)
The _____/______ virus has a viral envelope derived from the T-helper white blood cells.
These are viruses that attack bacteria.
Bacteriophages (A.K.A. Phages)
These are some of the largest and most complex viruses.
Viruses are not ______ organisms. They cannot be _______. They can be broken apart using chemicals though.
Viruses must have a host cell in order to reproduce. (They are considered _______ _________ _______. As the name indicates, viruses must get inside the host cell in order to reproduce.)
Obligate Intracellular Parasites
Viruses need to use the ____ cells ribosomes and enzymes to make new DNA or RNA strands and new capsomeres to form new viruses.
Refers to what organisms a virus can attack. It is determined by recognition of certain glycoproteins or glycolipids on the host cell membrane.
These enzymes, found in bacteria, act as primitive defense against viruses. These enzymes cut up the viral genome and thus inactivate the genes from being transcribed. They are called restriction enzymes because they only cut at certain nucleotide sequences. In other words, they are restricted in where they can cut.
a unique type of viruses. They use reverse transcriptase, an enzyme, to turn RNA into DNA. (It does transcription backwards. It turns “mRNA” into double stranded DNA, so that it can incorporate into the host DNA.
Examples of retroviruses (2)
Aids/Hiv and the common cold virus
Major viruses (4)
HIV/AIDS, Ebola, Influenza, SARS
Big Outbreak in one area
(Over 2,000 are known to exist.) (Big financial loss for farmers because of destroyed crops.)
(These are naked, infectious RNA molecules.) They attack plants only. (“oid” means “like”… they are “like” viruses as they are infectious.)